Synchronizer tester means for cameras



June 16, 1942. M. SCHWARTZ ETAL SYNQZ'IRQNIZER TESTER MEANS FOR CAMERASFiled March 21, 1939 4 Sheets-Sheet 1 F- 'IG .1

INVENTORS Wit A572; Mwaszraizw.

- ATTORNEY:

June 16, 1942. M.- SCHWARTZ ETALV 2,286,512

SYNCHRONIZER TESTER MEANS FOR CAMERAS Filed March 21, 1939 4Sheets-Sheet 2 June 1942- M SCHWARTZ ETAL SYNCHRONIZER TESTER MEANS FORCAMERAS Filed March 21, 1939 4 Sheets-Sheet 3 ATTORNEY.

M. sCHwA RTZ ETAL 2 SYNCHRONIZER TESTER MEANS FOR CAMERAS June16, 1942.

. 4 Shetg-Shet ,4

Filed March 21, 1939 F1634. FIGJS.

' INVENTOR5 87 ,032 [ammo Patented June 16, 1942 UNITED STATES 2,286,512SYNCHRONIZER TESTER MEANS FOR CAMERAS Morris Schwartz, New York,

dello, Huntington, N.

and mesne assignments, to The Kalart pany, Inc., New York, N.

New York and William Casteassignors, by direct Com- Y., a corporation ofApplication March 21, 1939, Serial No. 263,194

16 Claims.

Our invention relates to an apparatus for determining the adjustment ofa photoflash synchronizing unit that is mounted on a camera; said unitbeing used in connection with flashlight exposures.

An object of this invention is to provide a device for determining thecoincidence or the opening of a shutter of a camera with the flashing ofan optimum light emission from a flashlight.

A further object of this invention is to provide a device as describedwhich can be employed either as a stationary unit, or made applicablefor portable use.

A further object of'this invention is to provide an arrangement wherebya pair of movable slits through which light is projected are madeoperable through the medium of electro-magnet means, the movement ofsaid slits occurring simultaneously with the tripping of the camerashutter. These slits are visible when viewed through the shutter duringthe opening thereof regardless of the speed of exposure.

The vertical relation or spacing of these two slits will indicate thetiming of the photoflash synchronizer under test. The photoflashsynchronizer is provided with a means for adjusting its action andthereby controlling the timing of the shutter in relation to the momentof maximum illumination emitted from the flash bulb.

The synchronizer is adjusted until the two slits meet as viewed throughthe tester at the time of the shutters opening. The vertical separationbetween both slits will indicate to the viewer whether the shutter isopening early or late with regard to the peak of flash. An accurateguide for regulating the synchronizer by visible means is there-' byaflorded.

This invention has a coacting relation to our patent application forphotographic apparatus, Serial No. 220,444 which on December 1'7, 1940,issued as Patent No. 2,225,596 and operates in conjunction with thesame. The present invention, however, can also be used in connectionwith any other similar type of synchronizer unit.

In further description of our invention, attention is called to thedrawings in which:

Fig. 1 is a side view showing our synchronizer testing device inconnection with a camera.

F;g. 2 is a view of the synchronizer unit testing device shown in Fig. 1taken on a line 2-4 of said figure; also showing the relation of .thelight projecting slits when the synchronizer unit operates in advance ofthe shutter movement.

Fig. 3 is a detail view showing the position 55 the light slits-when thecamera shutter operates in advance or the synchronizer unit.

Fig. 4 shows the position of the slits when the shutter and synchronizerunit are synchronized.

Fig. 5 is a section taken on the line 5-5 of Fig. 1 showing themechanism for operating the slit plates.

Fig. 6 shows the position of the slit plates when in operation.

Fig. '7 is a section on the line of Fig. 2 showing the light source forsaid slits.

Fig. 8 is a circuit diagram, said circuit being used in connection withsaid testing device.

Fig. 9 is a sectional view showing a modiflcation of the slit platesused in the testing device.

Fig. similar in function Fig. 1.

Fig. 11 is a front view of the portable testing apparatus shown in Fig.10, taken on the line il-ll of Fig. 10.

Fig. 12 is a plan view of said apparatus taken on the line I2-l2 of Fig.11.

Fig. 13 is a section on a line l3--l 3 of Fig. 11.

Fig. 14 is a section through the mechanism of the testing apparatusshown in Fig. 10.

Fig. 15 is a section on the line l5-|5 of Fig. 14.

Fig. 16 shows a further view of said apparatus as shown in Fig. 15.

Fig. 1'7 shows a similar apparatus using slit plates instead of a slitdrum.

Fig. 18 is a section on the line 18-48 of Fig. 1'7

Fig. 19 is a section on a line I9l9 of Fig. 1'7.

Fig. 20 is a section on a line 20-20 of Fig. 14.

Referring to Fig. 1, the numeral designates a conventional camera. 3l isa shutter housing. 32 is a synchronizer unit similar in design to patentgranted to Morris Schwartz, No. 2,117,509, May 17, 1938. Thesynchronizer unit is screwed into a socket (not shown) of the shutterhousing 3|. 33 is a box like container in which the light source iscontained. The wiring 35 electrically connects the battery in thebattery case 36 to the light source in box 33.

A pair of connector tips 37, is inserted into sockets 33 of the box 33.The tips 31 are connected with the wiring 39 which extends into thesynchronizer unit 32. The synchronizer unit 32 isoperated through themedium of the cable release 40. The box 10 shows a portable testingapparatus to the apparatus shown in mounted on said standard 41 andwhich can be adjusted vertically through the medium of a thumb screw 43.The box 33 has a circular open- 33 is attached to a standard 41. Anadllustably mounted base plate 42 is also ing 44. A partition bar 45divides the opening 44 into two equal parts.

A pair of plates 46 and 47 (see Fig. 5) are located in the rear of theopening 44. The plate 46 has a narrow slit 48 and the plate 41 also hasa narrow slit 49. The plates 46 and 41 are hingably connected to an armmember 50 through the medium of auxiliary arm members 51X.

The arm member 50 hinges at the pivot screw 5| and is held under tensionof a spring 52. The tension of said spring 52 can be adjusted by meansof a manually operated arm 53 acting on said spring through the mediumof the spring connected arm 54. Said adjustment of the spring 52 bymeans of the arm 53 enables the operator of the testing apparatus toadjust the retractive speed of the member 50 after the release thereofby the armature 55 of the electromagnet 56. Said spring adjustment ismade in accordance with the time-speed of the particular type offlashlamp to which the synchronizer unit and camera shutter are to beadapted.

The arm member 50 is restrained from operating by means of a restrainingfinger armature 55.

A magnet 56 whenenergized actuates and attracts towards it therestraining finger armature 55, and thus releases the hingably mountedarm member 50. The release of said member 50 causes said member to swingupwardly under the impulse of the spring 52, and finally causes saidmember to settle down to the position shown in Fi .6.

5 pair of contact springs 51 which are normally closed will open whenthe hingably mounted arm member 50 is released (see Fig. 6). The contactsprings 51 are electrically connected to the battery 36. The opening ofsaid contacts W111 break said electrical connection and will disconnectthe flow of current from said battery 36. -To return the hingablymounted arm 50 to its original position shown in Fig. 5, the bar 500: isdepressed downwardly. The aforesaid movement will close the contactswitch 51. The switch 51 serves the function of a safety switch inavoiding a short circuit of the battery 36. Immed1ately upon the closingof the contacts 1n the synchronizer unit 32, consequent to the set-offthereof, the magnet 56 attracts the armature 55 which action opens thecontact switch as shown in Fig. 6. In this manner the circuit 3 9 isopened, and, in the event of a short c1rcu1t of the contactingarrangement in the synchromzer unit aforesaid, a short circuit of thebattery 36 is thus prevented.

Operation.

When photographing pictures with a camera equipped with a synchronizerunit, it is very important that there should be but a negligible lapseof time between the tripping of the shutter and the functioning of thesynchronizer unit, since a few thousandths of a second may mean thedifference between the success and failure of a picture exposure. Thereduction or practical elimination of the time variation referred to ismade possible by the novel testing device comprising the presentinvention. The device aforesaid checks the adjustment of thesynchronizer unit and enables the operator to bring said unit intocorrect timing relation with the tripping of the camera shutter: forinstance, to adjust the synchronizer unit sothat the midpoint-of theshutter opening period will occur approximately .22 sec. after the timethat the circuit is closed through the flash lamp. It is obvious that it5 necessary to change the adjustments of the synchronizer unit on aparticular camera to conform .to the movement of the shutter aforesaid.The arrangement and adjustment referred to result in a maximumpercentage of successful pictures.

The usual tests of the synchronizer unit in connection with a camerashutter are made through the medium of a circuit including saidsynchronizer unit, a flashlight and a battery. The flashlight will flashat the time set through the adjustment oi. the synchronizer as stated.

Since it is necessary to obtain coordination of the functioning of asynchronizer unit with that of its companion shutter operating inconnection therewith, in order to obtain perfect picture exposures, itis essential to provide testing means to accomplish the aforesaidresults Tests involving the use of flashlights to obtain correctrelation for the timing of said synchronizer unit and the camera shutterare obviously expensive.

In the utilization of our invention, the need for a flashlight bulb iseliminated by the utilization of the apparatus comprising the testerarrangement including the lamp bulb 34 shown in Fig. 1 which is locatedinside the box 33; also the lamp 34a; shown in Fig. 10, the latterarrangement being a modification of that shown in Fig. 1 and which isthe preferred embodiment of our invention.

The light from the light source 34 passes through the slits 48 and 49(Figs. 3 and 4)- and also through the objective lens and shutter housing3| shown in Fig. 1; and likewise in Fig. 10, the light from the lightsource 34:: passes through the camera 30 and through the cameraobjective 31m, and is observed through the aperture 59 of the testerunit 33m.

The operator in testing a synchronizer unit scans through the cameraobjective 3| as shown in Fig. 1, or through the aperture 59 as shown inFig. 10.

Since the plates 46 and 41 move upon the functioning of the arm member50 when the magnet 56 is energized, the slits 48 and 49 will movereciprocally relative to each other; the plate 46 moving upward as theplate 4.! moves downward. The slits 48 and 49 will be in coincidencewith each other as shown in Fig. 4 if the camera shutter of theobjective 3| and the synchronizer unit 32 are in operative synchronousrelation with each other.

If the synchronizer unit 32 lags behind the shutter movement, theposition of the slits 48 and 49 will appear as shown in Fig. 2, and whensaid synchronizer unit operates in advance of the movement of the camerashutter, the positions of the slits appear as shown in Fig. 3.

Referring to Fig. 9, which is a modification of the slit arrangementshown in Figs. 2, 3 and 4. The slits 48 and 49 are viewed through thehorizontal aperture 49a, and when said slits are in horizontalcoincidence with respect to each other, a continuous line of light fromthe light source 34 is observed along the entire horizontal length ofthe aperture 49a.

Referring to Fig. 10. In said figure there is shown an arrangementwhereby the synchronizer unit 3211 can be synchronized with the camerashutter' 3| 9: through the medium of the portable testing unit 33m. Theunit 33.1: comprises a recggngular container 58 having a. viewingopening The container 58 is supported on a pair of legs 60, said legs 60being inserted into tubular mem- III, II are 2,286,512 bers 6| in such amanner that the container 58 can be slid up or down on the legs 60, andin this manner enabling the proper leveling of the opening 59 with thatof the camera shutter Six. The slits 48m and 491: are observable throughthe opening 59 as shown in Fig. 11.

The rear portion of the container 58 has 3. rec-- tangular opening 62through which the light from the light source 34:: projects through theslits 48m and 49:: upon the momentary opening of the camera shutter.Inside the container 58 there is provided a solenoid magnet 63, said magnet having a plunger armature 64. Said armature 64 is secured to aflexible connecting arm 65 which in turn is fastened to a U-shapedmember 65. A drum 61 which has cut out portions 68 and 69, and alsoslits III and I! is rotatably mounted on a pair of trunnion screws I2.The extending portions 66:: of the U-shaped member 66 are secured to thedrum 61 at 68m. The wiring of the solenoid magnet 63 is held in positionby screws 12:12. Contact plates I3 which contact with the screws whichare held by a Bakelite plate It.

A pair of contact springs It and Il held on the Bakelite plate 15.

The springs I6 and II contact with the pin I8. The lower part I82: ofthe pin I8 is insulated and when the solenoid plunger armature G ismoved upward, said movement pushes the pin I8 in such a manner so thatthe insulated portion I82: will be located between the springs .16 and11, thus breaking the flow of the current, said disconnection preventingthe unrequited use of the battery. To restore the electric connectionthe pin I I8 is pushed downward.

When the solenoid plunger 64 is in normal position as shown in Fig. 14,the spring contacts '16 and II contact with the slidably mounted bar I8,thus completing an electrical circuit. The afore said circuitis brokenwhen the solenoid 63 is en 122 are attached to prongs Id are alsoergized as the plunger armature 64 willthen move upward therebyseparating the spring contacts "Sand 11' through the medium of theinsulated portion of the bar I8.

Referring again to Fig. 10. When checking the synchronization of thesynchronizer unit 321: and the camera shutter 3lx, alight source 342 isplaced in the rear of the camera ground glass. In Fig. 1 and similarlyin Fig. 10, the light from the lightsource 34 (Fig. 1), and the lightsource 341: (Fig. 10) passes through said ground'glass 301:. In Fig. 10the connectors I4 are electrically connected to a battery case 36::through the medium of the wiring- 3511:. The circuit arrangement of thewiring as described is shown in Fig. 8.

In the case of the testing device 332:, the slits located on the druminstead of on flat plates as shown in Fig. 5, but the result of the tzstis similar to that obtained with the device shown in Fig. 1. In otherwords, if the synchro nizer unit 32:: and the camera shutter Ila:operate in unison, at the time of the optimum opening of the camerashutter Slz, the slits II, II will be on a straight line with respect tothe observer viewing said slits through the opening 59 of the testingdevice 332.

To facilitate the observation of the position of the slits, a U-shapedbar 19 is provided for sighting. The drum 61 is rotated around thetrunnion pins I2 when the solenoid magnet 63 is energized.

To close the circuit 'for' operating the magnet 63, the operatordepresses the bar I4 thus re- '55 ter to be tested by slidingsynchronizer unit is correctly storing the electrical connection of thecontact springs I6 and 11 (Fig. 20).

In Figs. 1'7, 18 and 19 there is shown a testing device similar to thatshown in Fig. 14, with the difference, however, that, instead of a drum6! being employed, slidably mounted plates 46:: and 41s: are usedin amanner similar to that shown in Fig, 5.

Plates 46m and 41:: have slits 48a: and 491:, and said plates arebalanced on a hingably mounted bar 50x.

When the plate 4Gx'is moved upwards through the medium of the solenoidplunger armature 84, the plate 41:: will move downward due to the actionof the pivoted member 503. 1

The operation ofthis apparatus is similar to that shown in Fig. 14,.butin this case, however, no sighting bar is needed, since the slits are ona horizontal plane whereas in the device shown in Fig. 14 the slits arelocated one back of the other. To facilitate the afflxing of the testingapparatus in front of the camera shutter, a pair of fiat hingablymounted plates (Fig. 13) are secured to the bottom of the legs 60through the medium of the milled knob 85.

The plates aforesaid can be adjusted to fit the base plate of anycamera.

Referring to Fig. 11. For the purpose of adjusting the'position of theslits 48a: and 49a: of the testing device 33x, a dial 82 is rotatablymounted on a screw 83. Markings 84 with designations from 0" to 5" areaffixed in said dial 82. A-pin 84a: is-fastened to the dial 82. Saidpin840: contacts with the slidably mounted plate 41:: (see Fig. 1'1).

When the position of required to be adjusted, the dial 82 manually. 7

The apparatus herein described and embodying our invention. whichwe'hav'e termed a Synchroscope and is electrically operated through themedium of the circuit including shown in Fig. 8. The apparatus aforesaidgives a visual indication of the shutter-timing in relation to flashpeak intensity. The aforesaid the slits 48a and 49a: is is rotatedfunction is accomplished without the need for 1 a flash bulb or otherfacility or material.

the lens.

The dial arrangement as shown in Fig. provided for different time lagintervals associated with the various flash bulbs now on the market.

As shown in Figs. 1 is fastened in front of the camera lens and shut theadjustable crossed bars 80 in the camera track. The viewing window israised or lowered in height to center with Electrical connection isestablished v with the battery by means of the electrical cordconnection as shown in Fig. 10. The small plunger projecting through thetop of the testing device is gently pushed down, the synchronizer unitattached to the battery is wound and the shutter cocked. The' shuttercan be set for a speed of ,5 sec. or the maximum shutter speed asdesired. The back of the camera is then opened and exposed to a stronglight such as daylight, or an electric lamp such as the lamp 341:, Fig.10.

Gazing directly into the front window of the testing device, thesynchronizer is released in the usual way by pressing the cable releaseand then noting the position of the two sli The adjusted if the is ofpreferably small dimensions thesynchronizerunit as and 13 the testingdevice two slitsdfla: and 49.1: are seen end to end as one line-. h I

If. the'left slit is somewhat higher than the slit to thc right as shownin Fig. 11, the shutter is opening too early. The synchronizer unit istherefore adjusted by decreasing the spring tension behind the plunger apoint or two. The test is then repeated until the desired position ofthe two slits is attained. If the position of the two slits is otherwisethan as stated, that is, the right slit is lower, the latter positionwill indicate that the shutter is somewhat late in opening and thesynchronizer unit can then be adjusted to advance the shutter action byturning the milled tension knob of said synchronizer unit up a point ortwo.

When the two slits are lined up end to end with no appreciable verticalseparation, the synchronizer unit is correctly adjusted for theparticular shutter on the camera, and may be used with the flash bulbfor which the dial adjustment on the testing device has been set. Whenchanging over to another type of lamp, which is either later or earlierin time lag, the dial 82 is set correspondingly.

In the foregoing description of our invention, it will be seen that ourinvention is capable of considerable variation without departing fromthe spirit of said invention.

What we claim is:

1. In an apparatus for determining the synchronization of the optimumopening of a camera shutter with the peak intensity illumination 01 aphotofiash bulb, said synchronization being obtained through theadjustment of a synchronizer unit associated with the objectiveincluding said camera shutter for tripping the shutter, said apparatusincluding a tester unit mounted in line with the axis ofthe lens of saidcamera objective, said apparatus having a light source in connectiontherewith, a pair of members mounted for movement in opposite directionsin said tester unit, a slit in each of said members through which thelight from said light source may project, an electro magnetic device forcontrolling the operation of said slidable members, a circuit includingsaid electro-magnetic device, a battery and said synchronizer unit, saidelectro-magnetic device made operable through the medium of switchreleasing means in said synchronizer unit; and the position of saidsliding members and the slits therein on the opening of said camerashutter by the operation of said.

synchronizer unit determining the time of the opening of said shutterrelative to the operation of the switch release of said synchronizerunit whereby to enable the adjustment of said synchronizer unit.

2. In apparatus of the class described, said apparatus including acamera, a synchronizer unit for synchronizing the ignition of aphotofiash bulb with the tripping of the camera shutter associated withthe objective of said camera, a tester unit and a light source mountedin line with the lens of said camera, a pair of slidable members movablein opposite directions in said tester unit, slits in said slidablemembers through which the light from said light source may project,anelectro-magnet in said tester unit with an armature in latchingrelation with a pivoted arm member linked to said slidable members,adjustable spring means attached to said pivoted arm member for movingthe same in one direction, the adjustment of said spring meansdetermining the rate of movement of said arm member thereby so that saidslidable members move from a normal latched position to a position withthe slits therein opposite one another in a time interval correspondingto the rate of speed of a photofiash bulb when ignited by saidsynchronizer unit, said electro-magnet, a battery, and said synchronizerunit included in a circuit in said apparatus, the set-off of a switch insaid synchronizer unit causing the energization of said magnet and theconsequent movement of the armature thereof, said armature movementcausing the release of said pivoted arm member for movement by saidadjustable spring means to thereby cause movement in opposite directionsof said slidable members whereby the position of said slits at the timeof the full opening of said camera shutter as viewed therethroughindicates the time relation of said shutter opening operation and thephotoflash bulb igniting operation of said synchronizer unit.

3. In an apparatus for determining the synchronization of the optimumopening of a camera shutter with the peak intensity illumination of aphotofiash bulb, said synchronization being obtained through theadjustment of a synchronizer unit associated with the objective of saidcamera, said apparatus including a tester unit and a light source, saidtester unit being positioned in line with the axis of the lens of thecamera under test, a pair of slidable members movable in oppositedirections relative to each other in said tester unit, slits in saidslidable members through which the light from said light source mayproject, an electric circuit included in said apparatus, said circuitincluding a switch in said synchronizer unit, an electro-magnetic deviceand a source of potential, and means including said electro-magneticdevice whereby said slidable members are made primarily operable throughthe set-01f of the releasing means of said synchronizer unit so that theposition of said slits at'the time of the optimum opening of said camerashutter indicates the adjustment of said synchronizer unit.

4. In an apparatus for determining the synchronization of the optimumopening of a camera shutter with the peak intensity illumination of aphotoflash bulb, said synchronization obtained through the adjustment ofa synchronizer unit attached to said camera shutter, said apparatusincluding a light source and a testing unit and means for mounting saidtesting unit and said light source in line with the central axis of alens in the camera shutter, a pair 01 members mounted for slidingmovement in opposite directions in said testing unit, an electromagneticdevice in said testing unit controlling the movement of said members,slits in said slidable members through which the light from said lightsource may'project, said el-ectro-magnetic device, a battery and aswitch in said synchronizer unit included in a circuit in saidapparatus, means operated by the set-oil of said switch in saidsynchronizer unit and the tripping of said camera shutter thereby tocause the closing of said circuit and the consequent energization ofsaid electro-magnetic device to efiect movement of said slidable memberswhereby the relative positions of the slits in said slidable membersdetermine the synchronization of the opening of said camera shutter andthe set-off of said switch in said synchronizer unit.

5. In apparatus for determining the synchronization of the optimumopening of a camera. shutter with the peak intensity illumination ofaaeasre the'jcamera shutter contained therein, said apparatus includinga tester unitand a light source,

a pair of slidable members mounted for sliding movement in oppositedirections in said tester unit, a slit in each of said members throughwhich the light from said light source projects, said slidable membersmade operable through the medium of electro-magnetic means in saidtester unit, said electro-magnetic means, a source of a safety contactswitch included in said circuit and other means controlled by saidelectromagnetic device for operating said switch to open said circuit tosaid electromagnetic device after the energization thereof.

10. The structure as set forth in claim 4, said electro-magnetic deviceincluding an electropotential and said synchronizer unit included in Y acircuit in said apparatus; means operated by the set-oil? of saidsynchronizer unit for causing the momentary closing of said circuit andthe consequent energization of said electro-magnetic means to therebycause the movement of said slidable members; the position of said slitsat the time of opening of said shutter indicating the time relation ofsaid shutter opening and the photoflash bulb igniting operation of saidsynchronizer unit, whereby said synchronizer unit may. be adjusted untilsaid slits in said slidable members are in line with each other, andmanual resetting means in said tester unit for resetting the samepreparatory to the next folv with a camera magnet with an armatureassociated therewith, a pivoted arm member, a retractile spring attachedto said arm member, said armature normally blocking movement of said armmember by said spring, said arm member having a pair of auxiliary linkmembers pivotally attached thereto, said auxiliary link members beingpivotally connected to said slidable members whereby the movement ofsaid arm member by said spring causes the movement of said slidablemembers on the operation of said armature by the energization of saidelectro-magnet.

11. In a device of the type described for testing a synchronizer unitemployed in conjunction and a photofiash bulb whereby the bulb isignited and the camera shutter tripped in timed relation so at fullopening during the maximum illumination, a pair of movable members withslits therein, said members being movable in opposite dilowing set-offtest of the synchronizer unit aforesaid.

6. The structure as set forth in claim 4, wherein said. mounting meansincludes an adjustable support for said testing unit, said supportadjustably mountable on the carriage of the camera, said tester unitvertically slidable in' said support whereby an aperture in said testerunit may be moved into sighting coincidence with the camera objectivethereby enabling the sighting of said slits which are illuminated bysaid light source during the opening period of the shutter aforesaid.

'7 In apparatus for determining the synchronization of the optimumopening of a camera shutter with the peak intensity illumination of aphotoflash bulb, said synchronization being obtained through theadjustment of a synchronizer unit attached to said camera shutter; saidapparatus including atester! unit adapted to be positioned in line withthe axis of the lens of the shutter of. the camera under test, saidapparatus also having "a light source included therein, said tester-unitcomprising a pair of slidable members movable in opposite directions.relative to each other,

slits in said slidable memthe said predetermined location relative timeof theshutter tripping and photo-- bers through which the light fromsaid light sourcemay project, an electro-magnetic device for controllingthe operation of said slidable members, circuit connections forcontrolling the electro-magnetic device including a power source 8. Thestructure as set forth in claim 3, said' electro-magnetic deviceincluding a solenoid magnet, a plunger armature movable in said solenoidmagnet, said armature operably' connected with said slidable members.

9. The structureas set forth'in claim"? and rections relative to oneanother, means for adjusting the time of movement ofsaid members fromnormal positions to place the'slits therein in predetermined location tocorrespond to the ignition-maximum illumination characteristics ofvarious photoflash bulbs, means controlled by said synchronizer unit toinitiate the movement of said movable members from said normal positionsand to trip said'camera shutter, a source of light in line with thecentral axis of said camera shutter and said movable members, meansincluding said source of light for determining the position of theslits-in said members on the full opening'of said camera shutter, thesaiddetermined position of said slits relative to indicating the flashbulb igniting operation of said synchronizer unit whereby saidsynchronizer unit may be adjusted.

12. The structure as set forth in claim .11, wherein the means foradjusting the time of movement of said movable members from said normalpositions to place the slits therein in predetermined locations includesmeans for [changing the 'normalpositions Of said movable members.

' 13. The structure as set forth in claim 11 and electromagnetic means,means controlled by said electromagnetic means for initiating themovement ofsaid movable members, a source of potential and a normallyopen primary switch ,op erated by said synchronizer unit for closing acircuit from said source of potential to said electro-magnetic means, anormally closed secondary switch in said circuit and means operativeconcomitantly with the operation of said movable members for openingsaid secondary switch. Y 14. The structure as set forth in claim 11 andelectromagnetic means, means controlled by said electromagnetic meansfor initiating the movement of said movable members, a source ofpotential and a normally open primary switch operated by saidsynchronizer unit for closing a circuit from said source of potential tosaid electro-magnetic means, a normally closed secondary switch in saidcircuit, means operative concomitantly with the operation of saidmovable that the shutter is substantially opposite the slits in saidmovable 10 members.

16. The structure as set forth in claim 11 and including a resilientspring means tending to move said movable members from said normalpositions and means for adjusting the tension or said spring to vary thetime of movement of said movable members from said normal positions toplace the slits therein in predetermined locations.

MORRIS SCHWARTZ. WILLIAM CASTEDELLO,

